This is my code on C++. The wrong is in the test №6. Why? Help me, please.

#include <iostream>

using namespace std;

int main()
{
int k, n, sum=0, a, i, mas[100];
cin >> k >> n;
if (k>=1 && n<=100)
{

for (i=0; i <= n-1; i++)
{
 cin >> mas[i];
 if (mas[i] <= 100 && mas[i] >= 0)
 sum = sum + mas[i];
 else
 continue;
}

a = n * k;

if (sum > a)
 cout << sum - a << endl;
if (sum <= a)
 cout << 0 << endl;


}
return 0;
}